Trojan-Banker.Win32.Delf.ac / Insecure Permissions

[malvuln <malvuln13 () gmail com>]

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/81301fecc7d9ff6b28ac779d2f819673.txt
Contact: malvuln13 () gmail com
Media: twitter.com/malvuln

Threat: Trojan-Banker.Win32.Delf.ac
Vulnerability: Insecure Permissions
Description: Banker Win32.Delf.ac creates an insecure dir named
"BancoBrasil" under c:\ drive, granting change (C) permissions to the
authenticated user group. Standard users can rename the malware to disable
it or replace with their own executable. Then wait for a privileged user to
logon to the infected machine to potentially escalate privileges.
Type: PE32
MD5: 81301fecc7d9ff6b28ac779d2f819673
Vuln ID: MVID-2021-0126
Dropped files: DDA.exe
Disclosure: 03/14/2021

Exploit/PoC:
C:\>cacls BancoBrasil
C:\BancoBrasil BUILTIN\Administrators:(OI)(CI)(ID)F
               NT AUTHORITY\SYSTEM:(OI)(CI)(ID)F
               BUILTIN\Users:(OI)(CI)(ID)R
               NT AUTHORITY\Authenticated Users:(ID)C
               NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C


C:\BancoBrasil>dir
 Volume in drive C has no label.

 Directory of C:\BancoBrasil

03/12/2021  08:08 PM    <DIR>          bb
               0 File(s)              0 bytes

C:\BancoBrasil>cd bb

C:\BancoBrasil\bb>dir
 Volume in drive C has no label.

 Directory of C:\BancoBrasil\bb

03/12/2021  08:09 PM                 0 DDA.exe
03/12/2021  08:08 PM    <DIR>          loginpfe.bb_arquivos


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